Drought-stricken California is not the only place draining underground aquifers in the hunt for fresh water. It’s happening across the world, according to two new studies by U.S. researchers released Tuesday. Twenty-one of the world’s 37 largest aquifers – in locations from India and China to the United States and France -- have passed their sustainability tipping points, meaning more water is being removed than replaced from these vital underground reservoirs. Thirteen of 37 aquifers fell at rates that put them into the most troubled category. “The situation is quite critical,” said Jay Famiglietti, senior water scientist at NASA’s Jet...